Various types of medical instruments utilizing radiofrequency (RF) energy, laser energy and the like have been developed for delivering thermal energy to tissue, for example to ablate tissue and to cut tissue. Arthroscopic and other endoscopic electrosurgical tools often comprise treatment electrodes of different configurations where the tools may optionally be combined with irrigation and/or aspiration tools for performing particular minimally invasive procedures. Often the nature of the electrode limits use of a particular tool, and tools must be exchanged during a procedure to perform different tasks. For these reasons, it would be desirable to provide new and different designs for electrosurgical tools that allow the tools to be re-configured during a procedure to perform different tasks. At least some of these objectives will be met by the inventions described below.